New research

Nitrous oxide emissions could double by 2050, study finds

  • 28 Oct 2014, 17:42
  • Robert McSweeney

Emissions of nitrous oxide could double by the middle of the century if left unchecked, a new study finds. And nitrous oxide is the third biggest contributor to manmade climate warming. So should we be worried?

Laughing gas

Most people know nitrous oxide as 'laughing gas', used as a mild anaesthetic by doctors and dentists. But it is also a powerful greenhouse gas.

Nitrous oxide is the third-largest contributor to the manmade greenhouse effect, after carbon dioxide and methane.

A new study, published in the journal Environmental Research Letters, brings together all the projections for future nitrous oxide emissions from different researchers. The results show that on average emissions will increase 83 per cent by 2050, if we carry on with business as usual.

The study also looks at how emissions might be curbed between now and the middle of the century. If 'moderate' attempts are made, the study finds, nitrous oxides would still increase by around 26 per cent. But emissions could reduce by as much as 22 per cent if we really get our act together.

All the projections were made using a starting point of 2005. This means the researchers are able to see how actual nitrous oxide emissions in recent years compare to the different scenarios. And the bad news is that we're currently on the business-as-usual path, the researchers say.

Human activities

Bacteria release nitrous oxide naturally by breaking down nitrogen in the soil and oceans. Total emissions from natural sources are currently around twice those of emissions from human activities.

But while natural emissions have not changed significantly since the industrial revolution, manmade emissions have. This increase has caused nitrous oxide concentrations in the atmosphere to rise steadily since the the mid-19th century, as shown below.

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New study strengthens link between Arctic sea-ice loss and extreme winters

  • 26 Oct 2014, 19:11
  • Robert McSweeney

Declining Arctic sea-ice has made severe winters across central Asia twice as likely, new research shows. The paper is the latest in a series linking very cold winters in the northern hemisphere to rapidly increasing temperatures in the Arctic.

But the long-term picture suggests these cold winters might only be a temporary feature before further warming takes hold.

Arctic amplification

Temperatures in the Arctic are increasing almost twice as fast as the global average. This is known as Arctic amplification. As Arctic sea-ice shrinks, energy from the sun that would have been reflected away by sea-ice is instead absorbed by the ocean.

Arctic amplification has been linked with very cold winters in mid-latitude regions of the northern hemisphere. The UK, the US and Canada have all experienced extreme winters in recent years. Just last year, for example, the UK had its second-coldest March since records began, prompting the Met Office to call a rapid response meeting of experts to get to grips with whether melting Arctic sea-ice could be affecting British weather.

The new study, published in Nature Geoscience, suggests the likelihood of severe winters in central Asia has doubled over the past decade. This vast region includes southern Russia, Mongolia, Kazakhstan, and northern China. And it's the Arctic that's driving the changes once again, the authors say.

Pronounced change

The study finds that almost all of the very cold winters in central Asia during the past decade have coincided with particularly warm conditions in the Arctic.

The paper points to sea ice loss in the Barents Sea and the Kara Sea as the cause. These sit to the north of Scandinavia and Russia and to the south of the Arctic Ocean, as shown in the map below.

 

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US emissions increase hints at limitations of Obama’s clean power plan

  • 22 Oct 2014, 17:10
  • Mat Hope

US energy sector emissions increased slightly in 2013, according to new data from the Energy Information Administration (EIA). This may seem like bad news for President Obama, who has pledged to cut the country's emissions 17 per cent by 2020.

Obama unveiled his  clean power plan earlier this year to much fanfare. The centrepiece of the plan is to reduce emissions from electricity generation by 30 per cent by 2020.

The US's rising energy sector emissions seem to  suggest the policy may not be as effective as Obama hopes.

Obama's clean power plan specifically targets emissions from power generation, which accounts for   about 32 per cent of the US's total emissions. Cutting emissions from the US's homes and businesses is a much smaller part of his wider   Climate Action Plan.

The EIA's data shows the potential limitations of focusing on cutting power generation emissions without addressing the country's broader energy consumption.

Emissions increase

US energy sector emissions increased 2.5 per cent in 2013 compared to year before, the EIA's data shows. The EIA says the main reason for the increase was colder weather.

Winter temperatures at the start of 2013 were lower than a year before, and the US also experienced a particularly mild spring last year. Temperatures fell again later in the year, when the US was  engulfed by the polar vortex.

Screen Shot 2014-10-22 at 16.15.40.png
Source: National Oceanic and Atmospheric Administration, average monthly temperatures. Graph by Carbon Brief.

Households and businesses turned up their thermostats in response to the lower temperatures, which meant burning a lot more gas and a bit more oil. The residential sector was responsible for 48 per cent of 2013's emissions increase, mostly due to heat demand, the EIA says.

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